In medicine and related fields, it is well known to connect small tubing and instruments such as catheters or syringes using a type of lock known as a “luer lock.” By connecting catheters with other instruments, a doctor is aided in the removal or addition of fluids for the patient. Luer locks typically comprise two components that are connected. In one example, the first component is fixed, and the second component is rotatable. The fixed component includes a tube with an inner surface and an outer surface, the inner surface defining a passageway through which the liquid flows. The outer surface is coaxial with the inner surface and has a threaded portion that actually performs the locking function.
The rotating component includes a hollow cylinder coaxially surrounding a smaller, protruding inner tube through which liquid flows. However, this outer cylinder of the rotating component rotates freely about the inner tube along the common axis. The outer cylinder of the rotating component is threaded on its inner surface. The inside diameter of the outer cylinder of the rotating component corresponds to the outer diameter of the outer cylinder of the fixed component. Thus, when the outer cylinder of the rotating component is rotated about the outer surface of the fixed component, the threaded portions of the two elements interlock and the threaded portions and the cylinders interact to form a liquid-tight seal.
To aid in the locking of the two elements, manufacturers often place flanges on the outer surface of the outer cylinder of the rotating component. This gives the user more leverage with which to rotate the outer cylinder to ensure that the seal between the two elements is truly liquid-tight. An example of this can be seen in U.S. Pat. No. 4,294,250.
However, environments that medical devices are put in are often wet and slick. In these situations, even luer locks with a flanged head are difficult to manipulate. Any air or airborne contaminant entering the catheter can be dangerous or potentially fatal. Thus, there is a need to be able to securely engage the two elements of a luer lock to prevent leakage. Furthermore, the difficult and repeated actions of locking and unlocking the small luer locks can have a detrimental effect on the joints and muscles of the doctor, including promoting carpal tunnel syndrome.